Ethyl 3,4-di-O-benzoyl-2-O-benzyl-6-O-levulinoyl-1-thio-β-D-galactopyranoside

Ethyl 3,4-di-O-benzoyl-2-O-benzyl-6-O-levulinoyl-1-thio-β-D-galactopyranoside

Ethyl 3,4-di-O-benzoyl-2-O-benzyl-6-O-levulinoyl-1-thio-β-D-galactopyranoside is a synthetic thioglycoside designed for controlled reactivity in carbohydrate synthesis. Its structure combines orthogonal protecting groups to enable sequential deprotection during oligosaccharide assembly.

Structural Features

• Core: β-D-galactopyranoside backbone with an ethyl thio-group at the anomeric position (C1).
• Protection pattern:
  • Benzyl ether at O-2 (base-stable).
  • Benzoyl esters at O-3 and O-4 (acid-labile).
  • Levulinoyl ester at O-6 (acid-sensitive, selectively removable).

Synthesis Strategy

Based on analogous methods in the search results:

1. Selective benzylation at O-2 using benzyl bromide and a tin-based catalyst (e.g., di-n-butyltin oxide).
2. Benzoylation at O-3 and O-4 with benzoyl chloride under mild basic conditions.
3. Levulinoylation at O-6 via levulinic acid activation.
4. Final purification by column chromatography (hexanes:EtOAc gradients).

Physicochemical Properties

• Molecular formula: Estimated as C₃₄H₃₆O₉S (derived from substituent analysis).
• Appearance: White crystalline solid (common for similar thioglycosides).
• Solubility: Compatible with DCM, DMF, and chloroform.
• Storage: Stable at −20°C under inert atmosphere.

Applications

• Glycosylation intermediate: The levulinoyl group allows selective deprotection (e.g., using hydrazine acetate) to activate O-6 for further glycosylation.
• Orthogonal reactivity: Benzoyl (base-stable) and benzyl (acid-stable) groups enable sequential modifications in glycan synthesis.

Key Advantages

• Regioselective control: Strategic protection simplifies access to branched oligosaccharides.
• Compatibility: Stable under glycosylation conditions (e.g., N-iodosuccinimide/triflic acid).

This compound exemplifies advanced strategies in carbohydrate chemistry, balancing protective group orthogonality for precision in glycoconjugate synthesis.

Citations:

1. https://www.rsc.org/suppdata/d1/sc/d1sc06063e/d1sc06063e1.pdf
2. https://www.rsc.org/suppdata/d1/ob/d1ob00093d/d1ob00093d1.pdf
3. https://pubmed.ncbi.nlm.nih.gov/11028776/
4. https://synthose.com/products/EG773
5. https://www.glentham.com/en/products/product/GC7887/
6. https://www.bocsci.com/ethyl-3-4-di-o-benzyl-2-o-levulinoyl-b-d-thioglucuronide-benzyl-ester-item-1469.html
7. https://synthose.com/products/EG124
8. https://www.bocsci.com/product/ethyl-4-o-allyl-3-6-di-o-benzyl-2-o-levulinoyl-cas-2904756-10-9-96362.html